An acid-curable self-curing mold is produced by adding, to refractory particles made of silica sand or the like, a binder for self-curing mold formation that contains an acid-curable resin such as a furan resin, and a curing agent containing phosphoric acid, an organic sulfonic acid, sulfuric acid or the like, mixing these components with each other, filling the resultant mixed sands into an original pattern such as a wooden pattern, and then curing the acid-curing resin.
Examples of a resin usable as the furan resin include furfuryl alcohol, furfuryl alcohol/urea-formaldehyde resin, furfuryl alcohol/formaldehyde resin, furfuryl alcohol/phenol/formaldehyde resin, and other known modified furan resins. For example, Patent Documents 1 to 6 each discloses a binder composition for self-curing mold formation that contains a furan resin obtained by polycondensing furfuryl alcohol and an aldehyde as main components.